Ink jet printers are well known in the art. Generally, an ink jet printer includes an array of nozzles or orifices, a supply of ink, a plurality of ejection elements (typically either expanding vapor bubble elements or piezoelectric transducer elements) corresponding to the array of nozzles and suitable driver and control electronics for controlling the ejection elements. Typically, the array of nozzles end the ejection elements along with their associated components are referred to as a print head. It is the activation of the ejection elements which causes drops of ink to be expelled from the nozzles. The ink ejected in this manner forms drops which travel along a flight path until they reach a print medium such as a sheet of paper, overhead transparency, envelope or the like. Once they reach the print medium, the drops dry and collectively form a print image. Typically, the ejection elements are selectively activated or energized as relative movement is provided between the print head and the print medium so that a predetermined or desired print image is achieved.
Generally, the array of nozzles, supply of ink, plurality of ejection elements and driver electronics are packaged into an ink jet cartridge. In turn, the printer includes a carriage assembly for detachably mounting the ink jet cartridge thereto. In this manner, a fresh ink jet cartridge may be installed when the ink supply of the current ink cartridge has been consumed.
Recently, the postage meter industry and other envelope printing industries have begun to incorporate ink jet printers having a user replaceable ink jet cartridge. A typical postage meter (one example of a postage printing apparatus) applies evidence of postage, commonly referred to as a postal indicia, to an envelope or other mailpiece and accounts for the value of the postage dispensed. As is well known, postage meters include an ascending register, that stores a running total of all postage dispensed by the meter, and a descending register, that holds the remaining amount of postage credited to the meter and that is reduced by the amount of postage dispensed during a transaction. Because U.S. Postal Service regulations require that postage be paid in advance, it had traditionally been required that the user of a postage meter periodically present the meter to a Postal Service employee for recharging. However, more recently it is possible to recharge a meter remotely using telephone communications. At the time of recharging, the user pays to the Postal Service the amount of postage to be credited to the meter and the meter is recharged by increasing the setting of the descending register by the amount paid. The postage meter generally also includes a control sum register which provides a check upon the descending and ascending registers. The control sum register has a running account of the total funds being added into the meter. The control sum register must always correspond with the summed readings of the ascending and descending registers. The control sum register is the total amount of postage ever put into the machine and it is alterable only when adding funds to the meter. In this manner, the dispensing of postal funds may be accurately tracked and recorded.
Generally, the postage meter may be incorporated into a mailing machine, which is also well known in the art, for automated handling of the mailpieces. Mailing machines are readily available from manufactures such as Pitney Bowes Inc. of Stamford, Conn., USA and often include a variety of different modules which automate the processes of producing mailpieces. The typical mailing machine includes a variety of different modules or sub-systems where each module performs a different task on a mailpiece, such as: singulating (separating the mailpieces one at a time from a stack of mailpieces), weighing, sealing (wetting and closing the glued flap of an envelope), applying evidence of postage, accounting for postage used (performed by the postage meter), feeding roll tape or cut tape strips for printing and stacking finished mailpieces. However, the exact configuration of each mailing machine is particular to the needs of the user. Customarily, the mailing machine also includes a transport apparatus which feeds the mailpieces in a path of travel through the successive modules of the mailing machine.
To print a valid postal indicia the postage meter (accounting module) and the printer must work cooperatively to ensure that the value of the postal indicia which is printed is properly accounted for. Because there is a physical separation between the postage meter and the printer, there is a risk of fraud due to an intruder breaking into the communications between the postage meter and the printer.
One risk that is present is due to the user replaceable ink jet cartridge. When the ink jet cartridge is not present, print data signals from the print head controller are exposed to external interrogation at the ink jet cartridge connector. Thus, it would be possible to operate the mailing machine without the ink jet cartridge installed and capture the print data signals and replay them at a later time to produce fraudulent postal indicias.
Another risk is use of the mailing machine with an unauthorized printer. That is, if the unauthorized printer were capable of producing fraudulent postal indicias, then the mailing machine could be used to automate the handling and feeding of the mailpieces. In this manner, the exposure to fraud would be much greater than for a hand fed printer due to the increased throughput capabilities of the mailing machine. Thus, numerous fraudulent postal indicias could be produced.
Therefore, there is a need for a mailing machine including an ink jet printer having an ink jet cartridge wherein the mailing machine discourages fraudulent use of the mailing machine. More particularly, there is a need for preventing unauthorized interception of the print signals from the print head controller to the print head and unauthorized use of the mailing machine to feed and process envelopes. In this manner, the postal authority does not suffer a loss of funds.